1. Field
Embodiments of the invention relate generally to a nonvolatile memory device and a method for manufacturing the same.
2. Background Art
It is considered that bit density improvements have limitations for NAND type flash memory often used as nonvolatile memory devices. A cross-point nonvolatile memory device having a configuration in which, for example, a memory unit having a changeable electrical resistance is interposed between two electrodes has received attention as a nonvolatile memory device capable of having a so-called 4F2 element surface area, that is, a bit density higher than that of flash memory (JP-A 2007-184419 (Kokai)).
In other words, the element surface area of one memory cell of a cross-point nonvolatile memory device generally is 4F2 because the width of the interconnect is F and the spacing between the interconnects is F, where F is the minimum pattern line width of the lithography.
Further improvements of the bit density of cross-point nonvolatile memory devices are expected.
In the case where the bit density is increased, the interconnects become finer; the adhesion between the interconnects and the substrate weakens; and the reliability unfortunately decreases.